American researches have found an affordable way to prove the age of ivory which will close a loophole in international protection.

Trade in ivory is outlawed except for items acquired before 1989.

But it has been almost impossible to distinguish between legal ivory and tusks from elephants recently killed by poachers.

Scientists have now found a way to carbon date ivory which should stop poachers passing off fresh supplies as legal.

Dr Kevin Uno of Columbia University's Lamont-Doherty Earth Observatory, said: "We've developed a tool that allows us to determine the age of a tusk or piece of ivory, and this tells us whether it was acquired legally.

"Our dating method is affordable for government and law enforcement agencies and can help tackle the poaching and illegal trade crises."

The team tells the Proceedings of the National Academy of Sciences the system will also be able to identify the age of rhino horn.

Elephant and rhino poaching is now at record levels as demand for ivory for trinkets and horn for Traditional Chinese Medicine soars. More....